Vessels are used to contain substances such as fluids. A vessel is any hollow container including, for example, a container manufactured to hold a fluid (e.g., water, liquid, substance, or liquid/solid mixtures) and to facilitate the transfer of thermal energy to the substance (e.g., fluid) contained within. Examples of such vessels include pots, kettles, and the like.
Such vessels in the prior art such as pans or skillets typically include a flat bottom or a bottom that is indented around a perimeter of the bottom. Even with such an indentation, the bottom of such vessels is primarily flat. The bottom of the vessel is generally set against a heat source (e.g., flame or heating element). The heat source transfers thermal energy through the flat bottom of the vessel and into the fluid therein. There may be design elements or reinforcement elements on the vessel or the bottom of the vessel.
Marketing materials for vessels in the prior art tout the benefits of uniform heating. Uniform heating has merit if heating is purely by conduction (i.e., thermal diffusion), or, if the contents being heated are “fragile”, in the sense that they are subject to thermal degradation.
Essentially, the same vessel has been used worldwide. Differences in vessels of the same type are generally cosmetic, based on durability, based on ergonomics, or fabricated from different material(s).